I have a bunch of different sized heater hose and I was wondering if anybody has used this instead of the factory prebent hose for the bac and other things. I don't see why it would be a problem, but I don't know if I'm overlooking something obvious. Also, does anyone know the specs on all of the coolant hoses? Upper and lower radiator, bac, etc. - it would be great if someone knows all the inner diameters.

Don't have the sizes but I don't see why you can't use it. Just make sure there is no kink and that it fits right and then knock yourself out:)